I'm trying to come up with a budget and bill of materials for acquiring a Nybble kit and everything else reasonably needed to work with it and program additional and higher-level functions. Besides the kit, do I need to buy anything more than a Raspberry Pi 3 B+, batteries, and charger? I haven't messed with RP much; is ssh access to it adequate for programming higher-level functions? And what tools are necessary to customize the firmware and data on the NyBoard?
You need to but 14500 Li ion batteries and smart charger. Raspberry Pi is optional, and ssh should be adequate for programming higher level functions. It will communicate with the NyBoard through serial port. You can customized the NyBoard with Arduino IDE. And the original codes are on GitHub.